Maki Inoue-Choi1, Neal D Freedman1, Eiko Saito2, Shiori Tanaka3, Mayo Hirabayashi3, Norie Sawada3, Shoichiro Tsugane3, Yoshiaki Usui4, Hidemi Ito4, Chaochen Wang5, Akiko Tamakoshi6, Taro Takeuchi7, Yuri Kitamura7, Mai Utada8, Kotaro Ozasa8, Yumi Sugawara9, Ichiro Tsuji9, Keiko Wada10, Chisato Nagata10, Taichi Shimazu3, Tetsuya Mizoue11, Keitaro Matsuo12, Mariko Naito13, Keitaro Tanaka14, Kota Katanoda2, Manami Inoue3. 1. Metabolic Epidemiology Branch, Division of Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA. 2. Center for Cancer Control & Information Services, National Cancer Center, Tokyo, Japan. 3. Center for Public Health Sciences, National Cancer Center, Tokyo, Japan. 4. Division of Cancer Information and Control, Department of Preventive Medicine, Aichi Cancer Center Research Institute, Nagoya, Japan. 5. Department of Public Health, Aichi Medical University School of Medicine, Aichi, Japan. 6. Department of Public Health, Hokkaido University Graduate School of Medicine, Sapporo, Japan. 7. Department of Social Medicine, Osaka University Graduate School of Medicine, Osaka, Japan. 8. Department of Epidemiology, Radiation Effects Research Foundation, Hiroshima, Japan. 9. Division of Epidemiology, Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan. 10. Department of Epidemiology and Preventive Medicine, Gifu University Graduate School of Medicine, Gifu, Japan. 11. Department of Epidemiology and Prevention, Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo, Japan. 12. Division of Cancer Epidemiology and Prevention, Aichi Cancer Center Research Institute, Nagoya, Japan. 13. Department of Oral Epidemiology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan and. 14. Department of Preventive Medicine, Faculty of Medicine, Saga University, Saga, Japan.
Abstract
BACKGROUND: Increasing proportions of smokers in Japan smoke <10 cigarettes per day (CPD). Yet, the health risks of low-intensity smoking in Asia are poorly understood. METHODS: We performed a pooled analysis of 410 294 adults from nine population-based prospective cohort studies participating in the Japan Cohort Consortium. Cigarette-use data were collected at each study baseline in 1983-1994. Study-specific hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause and cause-specific mortality were calculated using multivariable-adjusted Cox regression by CPD among current smokers and by age at cessation among former smokers, with never smokers as the referent group. Pooled HRs and CIs were computed using a random-effect model. RESULTS: The smoking prevalence was 54.5% in men and 7.4% in women. About 15.5% of male and 50.4% of female current smokers smoked 1-10 CPD (low-intensity). Both male and female low-intensity smokers had higher all-cause mortality risks than never smokers. Risks were further higher with increasing CPD in a dose-response manner. HRs (95% CIs) were 1.27 (0.97-1.66), 1.45 (1.33-1.59) and 1.49 (1.38-1.62) for 1-2, 3-5 and 6-10 CPD, respectively, in men; 1.28 (1.01-1.62), 1.49 (1.34-1.66) and 1.68 (1.55-1.81) for 1-2, 3-5 and 6-10 CPD, respectively, in women. Similar associations were observed for smoking-related causes of death. Among former low-intensity smokers, younger age at cessation was associated with lower mortality risk. CONCLUSIONS: Smoking very low amounts was associated with increased mortality risks in Japan. All smokers should quit, even if they smoke very few CPD. Published by Oxford University Press on behalf of the International Epidemiological Association 2021. This work is written by US Government employees and is in the public domain in the US.
BACKGROUND: Increasing proportions of smokers in Japan smoke <10 cigarettes per day (CPD). Yet, the health risks of low-intensity smoking in Asia are poorly understood. METHODS: We performed a pooled analysis of 410 294 adults from nine population-based prospective cohort studies participating in the Japan Cohort Consortium. Cigarette-use data were collected at each study baseline in 1983-1994. Study-specific hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause and cause-specific mortality were calculated using multivariable-adjusted Cox regression by CPD among current smokers and by age at cessation among former smokers, with never smokers as the referent group. Pooled HRs and CIs were computed using a random-effect model. RESULTS: The smoking prevalence was 54.5% in men and 7.4% in women. About 15.5% of male and 50.4% of female current smokers smoked 1-10 CPD (low-intensity). Both male and female low-intensity smokers had higher all-cause mortality risks than never smokers. Risks were further higher with increasing CPD in a dose-response manner. HRs (95% CIs) were 1.27 (0.97-1.66), 1.45 (1.33-1.59) and 1.49 (1.38-1.62) for 1-2, 3-5 and 6-10 CPD, respectively, in men; 1.28 (1.01-1.62), 1.49 (1.34-1.66) and 1.68 (1.55-1.81) for 1-2, 3-5 and 6-10 CPD, respectively, in women. Similar associations were observed for smoking-related causes of death. Among former low-intensity smokers, younger age at cessation was associated with lower mortality risk. CONCLUSIONS: Smoking very low amounts was associated with increased mortality risks in Japan. All smokers should quit, even if they smoke very few CPD. Published by Oxford University Press on behalf of the International Epidemiological Association 2021. This work is written by US Government employees and is in the public domain in the US.
Entities:
Keywords:
Japan; Low-intensity smoking; cessation; cigarette; mortality; smoking; smoking-related death